Roy Moore speaks at a rally, in Fairhope, Alabama on 25 September 2017.
Photograph: Brynn Anderson/AP

Beleaguered Republican Roy Moore claimed on Friday he did not know the woman who has made underage sex allegations against him, as he faced renewed calls to step down from a crucial Senate race.

As the GOP cut its funding for the Alabama Senate candidate – up for election in one month’s time – two senators who had previously announced their endorsement of him, Mike Lee of Utah and Steve Daines of Montana pulled their support.

Lee tweeted late Friday afternoon: “Having read the detailed description of the incidents, as well as the response from Judge Moore and his campaign, I can no longer endorse his candidacy for the US Senate.”

Leigh Corfman told the Washington Post that Moore met her several times in 1979 when she was 14 and he was a local prosecutor aged 32. At one point he allegedly drove her to his home where he touched her over her underwear and guided her hand to touch him over his. They did not have sexual intercourse, according to the report.

As pressure grew on Friday for Moore to drop out of the Senate race, he sought to portray himself as the victim of a conspiracy. Speaking on Fox News host Sean Hannity’s syndicated radio show, Moore said: “I don’t know Ms Corfman from anybody. I never talked to her, never had any contact with her. The allegations of sexual misconduct with her are completely false. I believe they’re politically motivated.”

Three other women interviewed by the Washington Post said Moore, now 70, approached them when they were between the ages of 16 and 18 and he was in his early 30s.

Moore told Hannity, a leading conservative broadcaster: “With regard to the other girls, you understand this is 40 years ago and, after my return from the military, I dated a lot of young ladies.”

The former state judge acknowledged that he remembers two of the women named in the report: Debbie Wesson Gibson, who says she was 17 at the time, and Gloria Thacker Deason, who was 18. But he said “I don’t remember” and “I don’t recall specific dates” when pressed on details.

Moore said of Gibson: “I know her but I don’t remember going out on dates. I knew her as a friend.”

Later he seemed to shift position again, saying: “I don’t remember ever dating any girl without the permission of her mother.”

He denied serving Deason rose wine, saying that any date would have happened in a dry county. “She said she believed she was underaged. As I recall, she was 19 or older. I never provided intoxicating liquor to a minor. I seem to remember her as a good girl.”

Mitt Romney has joined other senior Republicans in calling for Roy Moore to drop out. Photograph: Evan Vucci/AP

Moore also said he and his team are conducting an investigation into the allegations. “This has waited over 40 years to bring a complaint four weeks out of an election. It’s obvious to the casual observer something’s up.”

Moore’s office also issued a fresh statement portraying himself as the true victim. “It has been a tough 24 hours because my wife and I were blindsided by an article based on a lie supported by innuendo,” he said.

“I have never provided alcohol to minors, and I have never engaged in sexual misconduct. As a father of a daughter and a grandfather of five granddaughters, I condemn the actions of any man who engages in sexual misconduct not just against minors but against any woman. I also believe that any person who has been abused should feel the liberty to come forward and seek protection.”

The White House has responded cautiously to the allegations so far. Press secretary Sarah Sanders said Donald Trump believes a “mere allegation”, particularly one from many years ago, should not be allowed to destroy a person’s life. But she also told reporters: “The president also believes that if these allegations are true, Judge Moore will do the right thing and step aside.”

Senate Republican majority leader Mitch McConnell has called on Moore to step aside in the Alabama Senate race if the allegations are true.

But other Republicans, including two of the party’s past presidential nominees, John McCain and Mitt Romney, have called on Moore to drop out. Romney, who is rumored to be considering a 2018 bid for the Senate, tweeted on Friday: “Innocent until proven guilty is for criminal convictions, not elections. I believe Leigh Corfman. Her account is too serious to ignore. Moore is unfit for office and should step aside.”

Two US senators who endorsed Moore in the primary, Ted Cruz of Texas and Rand Paul of Kentucky, did not respond to requests for comment from the Guardian about whether they still did.

On Friday it emerged from a Federal Election Commission filing that the National Republican Senatorial Committee is ending its fundraising agreement with Moore and its chairman, Senator Cory Gardner of Colorado, has described the allegations as “deeply troubling”.

But Moore remains defiant and insists he will not quit the race for the 12 December special election for attorney general Jeff Sessions’ former seat. His campaign denied the report as “the very definition of fake news and intentional defamation” and the Alabama Republican has long blazed a controversial path.

He has twice been removed as state supreme court chief justice for defying federal court orders, and Moore has long been known for incendiary statements including suggesting that “homosexual conduct” be criminalized.

At this point, Republicans have openly contemplating running incumbent Luther Strange, Moore’s opponent in the primary, as a write-in candidate, which could split the vote and help Moore’s Democratic opponent Doug Jones win. Alternatively, Republicans could simply let Moore get elected then expel him from the Senate.

He still has some vocal defenders. Steve Bannon, the former White House chief, condemned the Washington Post as part of the “opposition party” after it reported the allegations. The Axios website compiled a list of nine Alabama Republican officials who are standing by Moore.Jim Zeigler, the state auditor, told the Washington Examiner: “Mary was a teenager and Joseph was an adult carpenter. They became parents of Jesus. There’s just nothing immoral or illegal here. Maybe just a little bit unusual.”

Ed Henry, an Alabama state representative, was quoted by the Cullman Times, a daily newspaper in Cullman county, as saying: “If they believe this man is predatory, they are guilty of allowing him to exist for 40 years. I think someone should prosecute and go after them.”